Interfacial behaviors of p-type CeyFexCo4–xSb12/Nb thermoelectric joints

Interfacial diffusions and/or chemical reactions are one of the key issues for the reliability of CoSb3-based skutterudite thermoelectric (TE) joint, especially for the [Formula: see text]-type joint, which limits the applications of TE devices. We investigate the interfacial evolution for [Formula: see text]-type CeyFexCo[Formula: see text]Sb[Formula: see text]/Nb joints ([Formula: see text]–1, [Formula: see text], 3, 4) and combine the previous study on [Formula: see text]-type Yb[Formula: see text]Co4Sb[Formula: see text]/Nb joint to demonstrate the effect of TE materials on the interfacial microstructure and interfacial resistivity. The reaction–diffusion kinetic analysis shows that the TE materials has little effect on chemical reactions but strongly influence the Sb diffusions. The low energy barrier of Sb diffusion leads to the absent phase decomposition of skutterudites in CeyFexCo[Formula: see text]Sb[Formula: see text]/Nb joints. The interfacial resistivity of CeyFexCo[Formula: see text]Sb[Formula: see text]/Nb joints is related with Fe content and the interfacial reaction layer (IRL) growth. In addition, since the interfacial reaction layer growth rate and interfacial resistivity of CeyFexCo[Formula: see text]Sb[Formula: see text]/Nb joints are both low, Nb is an adequate barrier layer candidate material.

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Interfacial Microstructure and Joint Strength of Sn-Ag and Sn-Ag-Cu Lead Free Solders Reflowed on Cu/Ni-P/Au Metallization

Materials Science Forum ◽

10.4028/www.scientific.net/msf.512.355 ◽

2006 ◽

Vol 512 ◽

pp. 355-360

Author(s):

Akio Hirose ◽

Tomoyuki Hiramori ◽

Mototaka Ito ◽

Yoshiharu Tanii ◽

Kojiro F. Kobayashi

Keyword(s):

Solder Joint ◽

Interfacial Reaction ◽

Reaction Layer ◽

Joint Strength ◽

Aging Treatment ◽

Interfacial Microstructure ◽

Interfacial Reaction Layer ◽

Solder Balls ◽

Lead Free Solders ◽

Electroless Ni

Sn-3.5Ag (Sn-Ag) and Sn-3.5Ag-0.75Cu (Sn-Ag-Cu) solder balls were reflowed on electroless Ni-P/Au plated Cu pad with varying thickness of Au layer (0 to 500nm). In the Sn-Ag solder joint, a P-rich layer including voids, which resulted from Ni diffusion from the Ni-P plating to form Ni3Sn4 interfacial reaction layer, formed at the interface regardless of Au plating thickness. This caused the degradation of the joint strength. On the contrary, the Sn-Ag-Cu solder joint had no continuous P-rich layer formed and showed a higher joint strength than the Sn-Ag solder joint in the case of Au plating of 50nm or less. Cu alloying to the solder promote the formation of (Cu, Ni)6Sn5 instead to Ni3Sn4 as the interfacial reaction layer. The (Cu, Ni)6Sn5 reaction layer can suppress the diffusion of Ni from the N-P plating and thereby inhibit the formation of the P-rich layer. However, in the case of thick Au plating of 250nm or more, a thin P-rich layer formed at the interface even in the Sn-Ag-Cu solder joint and the joint strength was degraded. Au dissolving into the solder from the Au plating during the reflow process may encourage the diffusion of Ni from the Ni-P plating into the solder. As a result, the Sn-Ag-Cu solder joints with 50nm Au coating provided the best joint strength, although its joint strength considerably degraded after the aging treatment at 423K.

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Interface Behavior of Brazing between Zr-Cu Filler Metal and SiC Ceramic

Crystals ◽

10.3390/cryst11070727 ◽

2021 ◽

Vol 11 (7) ◽

pp. 727

Author(s):

Bofang Zhou ◽

Taohua Li ◽

Hongxia Zhang ◽

Junliang Hou

Keyword(s):

Interfacial Reaction ◽

Reaction Layer ◽

Chemical Potential ◽

Filler Metal ◽

Diffusion Constant ◽

Interface Reaction ◽

Diffusion Path ◽

Interface Behavior ◽

Interfacial Reaction Layer ◽

Sic Ceramic

The interface behavior of brazing between Zr-Cu filler metal and SiC ceramic was investigated. Based on the brazing experiment, the formation of brazing interface products was analyzed using OM, SEM, XRD and other methods. The stable chemical potential phase diagram was established to analyze the possible diffusion path of interface elements, and then the growth behavior of the interface reaction layer was studied by establishing relevant models. The results show that the interface reaction between the active element Zr and SiC ceramic is the main reason in the brazing process the interface products are mainly ZrC and Zr2Si and the possible diffusion path of elements in the product formation process is explained. The kinetic equation of interfacial reaction layer growth is established, and the diffusion constant (2.1479 μm·s1/2) and activation energy (42.65 kJ·mol−1) are obtained. The growth kinetics equation of interfacial reaction layer thickness with holding time at different brazing temperatures is obtained.

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